Gupta, Kalpna

Background: Mu opioid receptors (MORs) in peripheral tissues mediate adverse effects of opioids that impair health-related quality of life (HRQoL) and may stimulate cancer progression via mitogenic signaling. Naloxegol, a peripherally acting MOR antagonist (PAMORA), is approved for opioid-induced constipation. Safety and efficacy of naloxegol have not been evaluated concurrently with systemic cancer therapy. Methods: We conducted a randomized, double-blind, placebo-controlled trial of naloxegol in patients with advanced lung adenocarcinoma starting first-line systemic therapy. Results: Only 50 patients were enrolled; the trial was terminated early due to slow accrual. Two of the three components of the feasibility primary endpoint were not met (accrual and PRO completion). At 6 months, FACT-L emotional well-being was better with naloxegol (p = 0.0113). There were trends towards better Trial Outcome Index (p = 0.0505) and physical well-being (p = 0.0628) with naloxegol. Bowel function favored naloxegol for constipation (p = 0.0223), rectal pain during defecation (p = 0.0075), and abdominal pain from constipation (p = 0.0113). Adverse event frequency and severity, PRO-CTCAE, urinary hesitancy, pain scores, and progression-free and overall survival were comparable between naloxegol and placebo. Conclusions: Naloxegol appears to be safe and tolerable, with a signal of improved HRQoL and previously unappreciated benefit for emotional well-being, without adverse clinical outcomes. Our findings should be confirmed in larger studies. ClinicalTrials.gov ID: NCT03087708.

Abstract Like VEGF, morphine stimulates MAPK/ERK and Akt, leading to the promotion of angiogenesis via NO dependent signaling (Cancer Res62: 4491, 2002). Morphine acts via pertussis toxin (PT)-dependent G-protein coupled receptors (GPCRS), while VEGF acts via receptor tyrosine kinases (RTKs). We showed that PT-dependent GPCRs transactivate VEGF receptor-2/Flk1 via small GTPase RhoA (JBC277: 4679, 2002; JBC278:20738, 2003). Therefore, we hypothesized that morphine via the mu opioid receptor (MOR) transactivates Flk1 and promotes a pro-angiogenic microenvironment. Morphine-induced proliferation of human umbilical vein endothelial cells (HUVEC) was completely abrogated by Y-27632 (100 μM), a highly selective and potent inhibitor of Rho-associated protein kinases, suggesting the activation of Rho signaling by morphine. Addition of 1 μM morphine potentiated VEGF-induced (10 ng/ml) proliferation of HUVEC by 25%. We observed a 30% increase in intracellular calcium release after VEGF stimulation of HUVEC pre-incubated with morphine as compared to HUVEC pre-incubated with PBS, detected by a change in the fluorescence ratio of the Fura-2 AM dye. These findings show that morphine, via MOR and Rho signaling, transactivates Flk1 leading to the stimulation of calcium signaling and endothelial cell proliferation. To functionally corroborate our hypothesis, we used MOR knockout (MOR-KO) mice and injected them with MOR-replete T241 fibrosarcoma cells. T241 fibrosarcoma tumor growth in vivo showed appearance of palpable and measurable tumors 2 days earlier in wild type (wt) as compared to MOR-KO mice. Tumor growth and angiogenesis were decreased by 20–35% in MOR-KO mice as compared to wt littermates during 3 weeks of tumor growth. None of the MOR-KO showed signs of lung metastasis versus 40% wt mice with metastasis. Morphine (1.42 for the first 2 wks and 2.14 mg/Kg/day later, respectively) stimulated 20–35% tumor growth in wt, but not in MOR-KO mice. Western immunoblotting showed a 10-fold increase in the expression of phospho-Flk1 in morphine treated wt tumors as compared to PBS-treated wt mice. Morphine did not stimulate phospho-Flk1 expression in MOR-KO mice. Western analysis of immunoprecipitates obtained with α-MOR antibody showed the expression of Flk1 and phospho-Flk1 in wt, but were not expressed in MOR-KO tumors. Thus, MOR stimulates the transactivation of Flk1 in wt mice but not in MOR-KO. These in vitro and in vivo data using MOR-KO mice and the MOR agonist, morphine, show that MOR stimulates endothelial proliferation, angiogenesis and promotes tumor growth and metastasis directly as well as by transactivating Flk1 phosphorylation. We speculate that MOR is a critical component of the ‘angiogenic switch’, which regulates the pro-angiogenic and growth promoting tumor microenvironment. Thus, MOR provides a novel target for developing anti-angiogenic therapies.

AbstractElaboration of tumor necrosis factor (TNF) is a very early event in development of ischemia/reperfusion injury pathophysiology. Therefore, TNF may be a prominent mediator of endothelial cell and vascular wall dysfunction in sickle cell anemia, a hypothesis we addressed using NY1DD, S+SAntilles, and SS‐BERK sickle transgenic mice. Transfusion experiments revealed participation of abnormally activated blood monocytes exerting an endothelial activating effect, dependent upon Egr‐1 in both vessel wall and blood cells, and upon NFκB(p50) in a blood cell only. Involvement of TNF was identified by beneficial impact from TNF blockers, etanercept and infliximab, with less benefit from an IL‐1 blocker, anakinra. In therapeutic studies, etanercept ameliorated multiple disturbances of the murine sickle condition: monocyte activation, blood biomarkers of inflammation, low platelet count and Hb, vascular stasis triggered by hypoxia/reoxygenation (but not if triggered by hemin infusion), tissue production of neuro‐inflammatory mediators, endothelial activation (monitored by tissue factor and VCAM‐1 expression), histopathologic liver injury, and three surrogate markers of pulmonary hypertension (perivascular inflammatory aggregates, arteriolar muscularization, and right ventricular mean systolic pressure). In aggregate, these studies identify a prominent—and possibly dominant—role for an abnormal monocyte‐TNF‐endothelial activation axis in the sickle context. Its presence, plus the many benefits of etanercept observed here, argue that pilot testing of TNF blockade should be considered for human sickle cell anemia, a challenging but achievable translational research goal.